Avoid using styling tools that produce heat like curling irons, flat irons. The heat generated by these tools tend to damage hair significantly when used repeatedly. If you need to use these tools, use heat-protecting hair serum and set the tool to its lowest effective heat setting. You will also want to avoid using a blow dryer to dry your hair for the same reasons mentioned above. Air drying you hair allows your extensions to last longer. If you need to dry your hair right away, set your blow dryer to expel cold air instead of warm air. Otherwise, blow drying is a strict no-no.